The present invention is in the field of reporting on facts of or derived from a collection of facts organized as, or otherwise accessible according to, a dimensional data model. For shorthand throughout this description, such a collection of facts is referred to as a dimensionally-modeled fact collection. In particular, the present invention relates to reporting on facts considering the phenomena in which a specific grain value of dimension coordinates satisfying a (one or more) dimension coordinate constraint of a report query to a dimensionally-modeled fact collection may also be the value, at that grain, for other dimension coordinates that do not satisfy the dimension coordinate constraint.
It is known to respond to a query to a dimensionally-modeled fact collection by reporting on the facts contained in the dimensionally-modeled fact collection. Reports are typically generated to allow one to glean information from facts that are associated with locations in a dimensional data space according to which the dimensionally-modeled fact collection is modeled.
Locations in an n-dimensional data space are specified by n-tuples of coordinates, where each member of the n-tuple corresponds to one of the n dimensions. For example, (“San Francisco”, “Sep. 30, 2002”) may specify a location in a two-dimensional data space, where the dimensions are LOCATION and TIME. Coordinates need not be single-grained entities. That is, coordinates of a single dimension may exist at, or be specified with respect to, various possible grains (levels of detail). In one example, a coordinate of a LOCATION dimension comprises the following grains: CONTINENT, COUNTRY, CITY.
The order of the grains may have some hierarchical significance. The grains are generally ordered such that finer grains are hierarchically “nested” inside coarser grains. Using the LOCATION dimension example, the CITY grain may be finer than the COUNTRY grain, and the COUNTRY grain may be finer than the CONTINENT grain. Where the order of the grains of a dimension has hierarchical significance, the value of a coordinate of that dimension, at a particular grain, is nominally such that the value of the coordinate of that dimension has only one value at any coarser grain for that dimension. In an example, a value of a coordinate of a LOCATION dimension may be specified at the CITY grain of the LOCATION dimension by the value “Los Angeles.” This same coordinate has only one value at the COUNTRY and CONTINENT grains: “US” and “NORTH AMERICA”, respectively.